The indexing process has to be done in Sonos device memory, it isn’t done on the drives.

There is a hard-limit of 65K files and some soft limits based on the library data.

Sonos does try to select a Sonos device with a larger memory to create the index on if you try to start it from a low memory Sonos.

As Sonos has removed customer access to the data you need to see your only good option is to try to create an index. Within a few minutes of it failing you need to submit a diagnostic.

Once submitted you need to contact Sonos Support with the diagnostic ID number. Here or one of the methods on the contact page for your country.

Once you have the reason for the index failing post back here and folks can make suggestions to work around your issue.

Thank you very much for your reply and explanation Stanley_4. 

I’ll proceed with your suggestions how to approach the issue and perhaps be able to post how it went.